CN111474817A

CN111474817A - Wavelength conversion module and projection device

Info

Publication number: CN111474817A
Application number: CN201910067002.5A
Authority: CN
Inventors: 高尉华
Original assignee: Coretronic Corp
Current assignee: Coretronic Corp
Priority date: 2019-01-24
Filing date: 2019-01-24
Publication date: 2020-07-31
Also published as: US20200241403A1; US11300863B2

Abstract

A wavelength conversion module and a projection device are provided. The wavelength conversion module comprises a substrate, a first matching material layer, a wavelength conversion layer, a second matching material layer and a filling rubber material channel. The first matching material layer is located on the substrate. The wavelength conversion layer is located between the substrate and the first matching material layer and comprises a plurality of first holes, a wavelength conversion material and a combination material. The wavelength converting material is dispersed in the binding material. The second matching material layer is located between the substrate and the wavelength conversion layer. The filling rubber material channel is connected with the first matching material layer and the second matching material layer, the filling rubber material channel and the first matching material layer are made of filling rubber materials with the same material. The wavelength conversion module has good conversion efficiency, and the projection device has good optical quality.

Description

Wavelength conversion module and projection device

Technical Field

The present invention relates to an optical module and an optical device including the same, and more particularly, to a wavelength conversion module and a projection device.

Background

Recently, projection devices based on solid-state light sources such as light-emitting diodes (L ED) and laser diodes (laser diode) have been on the market, and since laser diodes have a light-emitting efficiency higher than about 20%, in order to break through the light source limitation of light-emitting diodes, pure color light sources for projectors are developed by exciting fluorescent powders with laser light sources.

However, in general, in the conventional process of manufacturing the phosphor wheel, the phosphor or the reflective material mixed with silica gel (Silicone) is coated on the substrate of the phosphor wheel to form the wavelength conversion layer or the reflective layer of the phosphor wheel, but the silica gel has the problems of non-high temperature resistance, degradation and the like, and thus when the phosphor wheel is excited by laser for a long time, the silica gel cannot resist high temperature and is easy to degrade or burn, which affects the light emitting efficiency and reliability of the phosphor wheel. On the other hand, another process for manufacturing a phosphor wheel is to mix phosphor or reflective material with inorganic adhesive material (e.g., glass cement or ceramic material) instead of silica gel to form the phosphor wheel. The phosphor wheel formed by the process has better heat conductivity and heat resistance, however, in the sintering or curing molding process of the phosphor wheel, some bonding agents, dispersing agents, additives and the like are volatilized into the air, so that holes are generated in the wavelength conversion layer or the reflection layer, and the holes are not communicated with each other, so that the air in the holes is difficult to be completely discharged or replaced by other materials. Moreover, since the refractive index of the air in the holes (approximately 1) is too different from the refractive index of the phosphor or glass (approximately 1.5), the air in the holes will reduce the light receiving amount of the phosphor layer of the phosphor wheel, thereby affecting the conversion efficiency.

The background section is only used to help the understanding of the present invention, and therefore the disclosure in the background section may include some known techniques which do not constitute the knowledge of those skilled in the art. The statements in the "background" section do not represent that matter or the problems which may be solved by one or more embodiments of the present invention, but are known or appreciated by those skilled in the art before filing the present application.

Disclosure of Invention

The invention provides a wavelength conversion module with good conversion efficiency.

The invention provides a projection device with good optical quality.

Other objects and advantages of the present invention will be further understood from the technical features disclosed in the present invention.

To achieve one or a part of or all of the above or other objects, an embodiment of the invention provides a wavelength conversion module. The wavelength conversion module comprises a substrate, a first matching material layer, a wavelength conversion layer, a second matching material layer and a filling rubber material channel. The first matching material layer is located on the substrate. The wavelength conversion layer is located between the substrate and the first matching material layer and comprises a plurality of first holes, a wavelength conversion material and a combination material. The wavelength converting material is dispersed in the binding material. The second matching material layer is located between the substrate and the wavelength conversion layer. The filling rubber material channel is connected with the first matching material layer and the second matching material layer, the filling rubber material channel and the first matching material layer are made of filling rubber materials with the same material.

To achieve one or a part of or all of the above or other objects, an embodiment of the invention provides a projection apparatus. The projection device comprises the wavelength conversion module, an excitation light source, a light valve and a projection lens. The excitation light source is used for emitting an excitation light beam, wherein the excitation light beam is transmitted to the wavelength conversion module, and forms an illumination light beam through the wavelength conversion module. The light valve is located on the transmission path of the illumination beam and is used for enabling the illumination beam to form an image beam. The projection lens is located on the transmission path of the image light beam and is used for enabling the image light beam to form a projection light beam.

Based on the above, the embodiments of the invention have at least one of the following advantages or efficacies. In the embodiment of the invention, the projection device and the wavelength conversion module can fill the first holes by using the filling rubber material through the filling rubber material channels formed by the first holes, so that the conversion efficiency of the wavelength conversion layer is improved. Moreover, the wavelength conversion module can also improve the transmittance of visible light by the configuration of the first matching material layer, so that the conversion efficiency of the wavelength conversion layer is improved. In addition, the projection device has good conversion efficiency and optical quality due to the adoption of the wavelength conversion module with good conversion efficiency.

In order to make the aforementioned and other features and advantages of the invention more comprehensible, embodiments accompanied with figures are described in detail below.

Drawings

Fig. 1A is a schematic cross-sectional view of a wavelength conversion module according to an embodiment of the invention. Fig. 1B is a top view of the wavelength conversion module of fig. 1A.

Fig. 2 is a schematic structural diagram of a projection apparatus according to an embodiment of the invention.

Fig. 3 is a schematic configuration diagram of another projection apparatus according to an embodiment of the invention.

Description of the reference numerals

50: excitation light beam

60: converting a light beam

70: illuminating light beam

80: image light beam

90: projection light beam

100: wavelength conversion module

110: substrate

120: wavelength conversion layer

130: a first matching material layer

140: second matching material layer

200. 300, and (2) 300: projection device

210: excitation light source

220: light splitting unit

220A: penetration zone

220B: reflection area

230: light filtering module

240: light homogenizing element

250: light valve

260: projection lens

BM: bonding material

CA: a first hole

FM: filling rubber material

FC: filling the rubber material channel

TR: light passing area

WM: wavelength conversion material

WR: a wavelength conversion region.

Detailed Description

The foregoing and other technical and scientific aspects, features and utilities of the present invention will be apparent from the following detailed description of a preferred embodiment when read in conjunction with the accompanying drawings. Directional terms as referred to in the following examples, for example: up, down, left, right, front or rear, etc., are simply directions with reference to the drawings. Accordingly, the directional terminology is used for purposes of illustration and is in no way limiting.

Fig. 1A is a schematic cross-sectional view of a wavelength conversion module according to an embodiment of the invention. Fig. 1B is a top view of the wavelength conversion module of fig. 1A. Referring to fig. 1A and 1B, the wavelength conversion module 100 of the present embodiment has at least one wavelength conversion region WR and a light passing region TR. Specifically, as shown in fig. 1A, the wavelength conversion module 100 includes a substrate 110, a first matching material layer 130, a wavelength conversion layer 120, a second matching material layer 140, and a filling adhesive channel FC. As shown in fig. 1A, in the present embodiment, the first matching material layer 130, the wavelength conversion layer 120 and the second matching material layer 140 are all located on the substrate 110, the wavelength conversion layer 120 is located between the substrate 110 and the first matching material layer 130, and the second matching material layer 140 is located between the substrate 110 and the wavelength conversion layer 120. Further, the first matching material layer 130, the wavelength conversion layer 120 and the second matching material layer 140 are disposed corresponding to the wavelength conversion region WR. In the present embodiment, the substrate 110 may be made of aluminum, aluminum alloy, copper alloy, aluminum nitride or silicon carbide, and has good thermal conductivity and heat resistance.

Further, as shown in fig. 1A, in the present embodiment, the wavelength conversion layer 120 includes a plurality of first holes CA, a wavelength conversion material WM, and a bonding material BM. The wavelength converting material WM is dispersed in the binding material BM. For example, in the present embodiment, the thickness of the wavelength conversion layer 120 is greater than or equal to 0.05 mm and less than or equal to 0.3 mm. In addition, in the present embodiment, the particle size range of the wavelength conversion material WM is between 5 to 500 nm. It should be noted that the numerical ranges are only used for illustrative purposes and are not used to limit the invention.

Furthermore, as shown in fig. 1A, in the present embodiment, the filling adhesive channel FC connects the first matching material layer 130 and the second matching material layer 140, the filling adhesive channel FC and the first matching material layer 130 have the filling adhesive FM with the same material. For example, as shown in fig. 1A, in the present embodiment, the second matching material layer 140 includes a filling paste material FM, the first holes CA in the wavelength conversion layer 120 can form filling paste material channels FC, and the filling paste material FM permeates into the filling paste material channels FC formed by the first holes CA of the wavelength conversion layer 120 through capillary action, and then forms the first matching material layer 130 on the surface of the wavelength conversion layer 120. Thus, the second matching material layer 140, the filling adhesive channel FC and the first matching material layer 130 simultaneously include the filling adhesive FM.

Specifically, in the present embodiment, the material of the filling adhesive material FM included in the second matching material layer 140, the filling adhesive material channel FC, and the first matching material layer 130 includes silicone, epoxy, alcohol-soluble inorganic adhesive, or water-soluble inorganic adhesive. For example, in the embodiment, the second matching material layer 140 includes a silicone rubber, an epoxy resin, an alcohol-soluble inorganic adhesive or a water-based inorganic adhesive, and the thickness of the second matching material layer 140 is less than or equal to 0.1 mm, but the invention is not limited thereto. In another embodiment, if the material of the filling adhesive FM included in the second matching material layer 140, the filling adhesive channel FC and the first matching material layer 130 includes silicone rubber with heat conductive material powder therein or epoxy resin with heat conductive material powder therein, that is, the second matching material layer 140 includes silicone rubber with heat conductive material powder therein or epoxy resin with heat conductive material powder therein, and the thickness of the second matching material layer 140 can be increased to be within a range of 0.2 mm or less.

For example, in the present embodiment, the range of the volume percentage of the first holes CA in the wavelength conversion layer 120 is greater than or equal to 5%. Thus, the first holes CA are easy to form the filling material channels FC, and the effect of the filling material FM penetrating into the wavelength conversion layer 120 through capillary action is significant, so as to fill the first holes CA and easily form the first matching material layer 130 on the surface of the wavelength conversion layer 120. For example, in the embodiment, the thickness of the first matching material layer 130 is greater than 0 and less than or equal to 30 μm, but the invention is not limited thereto.

For example, in the present embodiment, the refractive index ranges of the filling adhesive FM included in the second matching material layer 140, the filling adhesive channel FC, and the first matching material layer 130 are greater than or equal to 1.1 and less than or equal to 1.9. Thus, since the first holes CA are filled with the filling adhesive FM and have a refractive index close to that of the wavelength conversion material WM, the risk that the light receiving amount of the wavelength conversion layer 120 is reduced due to the existence of the first holes CA can be avoided, and the conversion efficiency of the wavelength conversion layer 120 is improved.

In view of the above, in the present embodiment, the refractive index of the first matching material layer 130 ranges from 1.1 to 1.9, and further, in the present embodiment, the refractive index of the first matching material layer 130 can be designed to be smaller than the refractive index of the wavelength conversion layer 120, for example, the refractive index of the first matching material layer 130 can be set to 1.2. Thus, since the visible light transmitted to the wavelength conversion module 100 first penetrates through the first matching material layer 130 and then enters the wavelength conversion layer 120, the transmittance of the visible light is about 98% according to the formula of the reflectance ratio and the transmittance ratio of the light penetrating through the interface of the different medium layers, which is calculated by the fresnel equation based on the refractive indexes of the different medium layers. In contrast, the transmittance of the conventional wavelength conversion module 100 without the first matching material layer 130 has a value of about only 96%. Accordingly, the wavelength conversion module 100 can improve the transmittance of the visible light by the configuration of the first matching material layer 130, and further improve the conversion efficiency of the wavelength conversion layer 120.

Specifically, in the present embodiment, the transmittance of the visible light having a wavelength band ranging from 400 nm to 700 nm through the first matching material layer 130 or the second matching material layer 140 is greater than 90%. In the present embodiment, the bonding material BM is an inorganic material, and includes silicon dioxide and metal oxide, and the transmittance of visible light with a wavelength range between 400 nm and 700 nm through the bonding material BM is greater than 90%. Thus, the visible light with the wavelength range between 400 nm and 700 nm has good transmittance for both the first matching material layer 130 and the second matching material layer 140, and is easy to enter into the wavelength conversion region WR.

In this way, the wavelength conversion module 100 can fill the first holes CA with the filling material FM through the filling material channels FC formed by the first holes CA, thereby improving the conversion efficiency of the wavelength conversion layer 120. Moreover, the wavelength conversion module 100 can also improve the transmittance of visible light by the configuration of the first matching material layer 130, thereby improving the conversion efficiency of the wavelength conversion layer 120.

Referring to fig. 1A, fig. 1B and fig. 2, a projection apparatus 200 includes an excitation light source 210, a light splitting unit 220, a wavelength conversion module 100, a light valve 250 and a projection lens 260. in the present embodiment, the structure of the wavelength conversion module 100 has been described in detail in the foregoing, and thus is not described herein.

As shown in fig. 2, in the present embodiment, an excitation light source 210 is used to emit an excitation light beam 50. In the present embodiment, the excitation light source 210 is a laser light source, and the excitation light beam 50 is a blue laser beam. For example, the excitation light source 210 may include a plurality of blue laser diodes (not shown) arranged in an array, but the invention is not limited thereto.

Specifically, as shown in fig. 2, in the present embodiment, the light splitting unit 220 is disposed on the transmission path of the excitation light beam 50 and located between the excitation light source 210 and the wavelength conversion module 100. Specifically, the light splitting unit 220 may be a partially transmissive and partially reflective element, a color separation element, a polarization splitting element, or other various elements that can split light beams. For example, in the present embodiment, the transmissive region 220A of the light splitting unit 220 can allow the blue light beam to pass therethrough, and provide a reflective effect for light beams of other colors (e.g., red, green, yellow, etc.). That is, the transmission region 220A of the light splitting unit 220 can transmit the blue excitation light beam 50, so that the excitation light beam 50 can pass through the light splitting unit 220 and be incident on the wavelength conversion module 100.

For example, as shown in fig. 1A, 1B and 2, the wavelength conversion module 100 is located on a transmission path of the excitation beam 50, and at least one wavelength conversion region WR of the wavelength conversion module 100 is used for converting the excitation beam 50 into at least one conversion beam 60, and the light passing region TR of the wavelength conversion module 100 is used for reflecting the excitation beam 50 so that the excitation beam 50 is transmitted to a subsequent optical element. The wavelength conversion module 100 further includes a first actuator (not shown) for allowing the light passing region TR and the at least one wavelength conversion region WR to enter the irradiation range of the excitation light beam 50 at different times, so as to selectively pass or convert the excitation light beam 50 into the at least one conversion light beam 60. Then, as shown in fig. 2, the excitation beam 50 and the at least one converted beam 60 from the wavelength conversion module 100 can be guided to the light splitting unit 220, and reflected by the reflective region 220B of the light splitting unit 220 to the subsequent filtering module 230.

For example, as shown in fig. 2, the projection apparatus 200 further includes a filter module 230, and the filter module 230 is located on the transmission path of the excitation beam 50 and the conversion beam 60 and has a filter optical area (not shown) and a light-transmitting area (not shown). The filter module 230 further includes a second actuator (not shown) for making the filter optical area (not shown) enter the irradiation range of the converted light beam 60 at different times to form a red color light and a green color light, respectively. On the other hand, the light-transmitting regions (not shown) also enter the irradiation range of the excitation light beam 50 transmitted to the filter module 230 at different times to form blue light. Thus, the excitation beam 50 and the converted beam 60 can be sequentially formed into the illumination beams 70 with different colors.

On the other hand, as shown in fig. 2, in the present embodiment, the projection apparatus 200 further includes a light uniformizing element 240 located on the transmission path of the illumination light beam 70. In the present embodiment, the light uniformizing element 240 includes an integration rod, but the present invention is not limited thereto. In more detail, as shown in fig. 2, when the illumination beam 70 is transmitted to the light uniformizing element 240 via the illumination system, the light uniformizing element 240 may uniformize the illumination beam 70 and transmit the illumination beam to the light valve 250.

Next, as shown in fig. 2, the light valve 250 is located on the transmission path of the illumination beam 70 and is used for forming the illumination beam 70 into the image beam 80. The projection lens 260 is located on the transmission path of the image beam 80 and is used for forming the image beam 80 into a projection beam 90, so as to project the image beam 80 onto a screen (not shown) to form an image frame. After the illumination beam 70 is converged on the light valve 250, the light valve 250 sequentially forms the illumination beam 70 into the image beams 80 with different colors and transmits the image beams to the projection lens 260, so that the image frame projected by the image beam 80 converted by the light valve 250 can be a color frame.

In this way, the wavelength conversion module 100 of the projection apparatus 200 can fill the first holes CA with the filling material FM through the filling material channels FC formed by the first holes CA, thereby improving the conversion efficiency of the wavelength conversion layer 120. Moreover, the wavelength conversion module 100 can also improve the transmittance of visible light by the configuration of the first matching material layer 130, thereby improving the conversion efficiency of the wavelength conversion layer 120. In addition, since the projection apparatus 200 employs the wavelength conversion module 100 with good conversion efficiency, the projection apparatus 200 may also have good conversion efficiency and optical quality.

In the foregoing embodiment, the projection apparatus 200 is exemplified by the wavelength conversion module 100 including the light passing region TR for reflecting the excitation light beam 50, but the invention is not limited thereto. In other embodiments, the light passing region TR of the wavelength conversion module 100 can also be used for passing the excitation light beam 50, and any person skilled in the art can make appropriate changes to the light path thereof after referring to the present invention, but it still falls within the scope of the present invention. Some examples will be given below as an illustration.

Fig. 3 is a schematic configuration diagram of another projection apparatus according to an embodiment of the invention. Referring to fig. 3, the projection apparatus 300 of the present embodiment is similar to the projection apparatus 200 of fig. 2, and the difference therebetween is as follows. In the wavelength conversion module 100 of the projection apparatus 300 of the present embodiment, the substrate 110 located in the light passing region TR has a hollow structure. That is, in the embodiment of fig. 3, the light passing region TR of the wavelength conversion module 100 is used to penetrate the excitation light beam 50.

Specifically, as shown in fig. 1B and fig. 3, in the present embodiment, when the light passing region TR of the wavelength conversion module 100 enters the irradiation range of the excitation light beam 50, the excitation light beam 50 penetrates the wavelength conversion module 100 and is transmitted to the filter module 230 through the light transmitting module L T, on the other hand, in the present embodiment, when at least one wavelength conversion region TR enters the irradiation range of the excitation light beam 50, the excitation light beam 50 is converted into at least one converted light beam 60 by at least one wavelength conversion region TR, and then, as shown in fig. 1A, at least one converted light beam 60 from the wavelength conversion module 100 can be guided to the light splitting unit 220 and reflected to the subsequent filter module 230, and the filter module 230 respectively forms the excitation light beam 50 and at least one converted light beam 60 into red light, green light and blue light, and thereby forms the subsequent illumination light beam 70 and image light beam 80.

In this way, the wavelength conversion module 100 of the projection apparatus 300 can fill the first holes CA with the filling material FM through the filling material channels FC formed by the first holes CA, thereby improving the conversion efficiency of the wavelength conversion layer 120. Moreover, the wavelength conversion module 100 can also improve the transmittance of visible light by the configuration of the first matching material layer 130, thereby improving the conversion efficiency of the wavelength conversion layer 120. In addition, since the projection apparatus 300 employs the wavelength conversion module 100 with good conversion efficiency, the projection apparatus 300 may also have good conversion efficiency and optical quality.

In summary, the embodiments of the invention have at least one of the following advantages or effects. In the embodiment of the invention, the projection device and the wavelength conversion module can fill the first holes by using the filling rubber material through the filling rubber material channels formed by the first holes, so that the conversion efficiency of the wavelength conversion layer is improved. Moreover, the wavelength conversion module can also improve the transmittance of visible light by the configuration of the first matching material layer, so that the conversion efficiency of the wavelength conversion layer is improved. In addition, the projection device has good conversion efficiency and optical quality due to the adoption of the wavelength conversion module with good conversion efficiency.

The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the invention, which is defined by the claims and the description of the invention, and all simple equivalent changes and modifications made therein are also within the scope of the invention covered by the claims and the description. Furthermore, it is not necessary for any embodiment or claim of the invention to address all of the objects, advantages, or features disclosed herein. In addition, the abstract and the title of the invention are provided for assisting the retrieval of patent documents and are not intended to limit the scope of the invention. Furthermore, the terms "first", "second", and the like in the description or the claims are used only for naming elements (elements) or distinguishing different embodiments or ranges, and are not used for limiting the upper limit or the lower limit on the number of elements.

Claims

1. The wavelength conversion module is characterized by comprising a substrate, a first matching material layer, a wavelength conversion layer, a second matching material layer and a filling rubber material channel, wherein: the first matching material layer is positioned on the substrate;

the wavelength conversion layer is located between the substrate and the first matching material layer, and the wavelength conversion layer comprises a plurality of first holes, a wavelength conversion material and a bonding material, wherein:

the wavelength converting material is dispersed in the binding material;

the second matching material layer is positioned between the substrate and the wavelength conversion layer; and

the filling rubber material channel is connected with the first matching material layer and the second matching material layer, the filling rubber material channel and the first matching material layer are made of filling rubber materials with the same materials.

2. The wavelength conversion module of claim 1, wherein the plurality of first voids comprise a range of greater than or equal to 5% by volume of the wavelength conversion layer.

3. The wavelength conversion module of claim 1, wherein the second matching material layer comprises the filling glue material, and the first matching material layer is formed on the surface of the wavelength conversion layer after the filling glue material penetrates to a part of the plurality of first holes of the wavelength conversion layer through capillary action.

4. The wavelength conversion module of claim 1, wherein the first matching material layer has a thickness greater than 0 and equal to or less than 30 microns.

5. The wavelength conversion module of claim 1, wherein the first matching material layer has a refractive index less than a refractive index of the wavelength conversion layer.

6. The wavelength conversion module of claim 1, wherein the first matching material layer has a refractive index in a range of 1.1 or more and 1.9 or less.

7. The wavelength conversion module of claim 1, wherein the second matching material layer comprises silicone, epoxy, alcohol-soluble inorganic adhesive, or water-based inorganic adhesive.

8. The wavelength conversion module of claim 7, wherein the thickness of the second matching material layer is 0.1 mm or less.

9. The wavelength conversion module of claim 1, wherein the second matching material layer comprises silicone gel with thermally conductive material powder therein or epoxy resin with thermally conductive material powder therein.

10. The wavelength conversion module of claim 9, wherein the thickness of the second matching material layer is 0.2 millimeters or less.

11. The wavelength conversion module of claim 1, wherein visible light having a wavelength band in a range of 400 nm to 700 nm has a transmittance of greater than 90% through the first matching material layer or the second matching material layer.

12. A projection device is characterized in that the projection device comprises a wavelength conversion module, an excitation light source, a light valve and a projection lens, wherein:

the wavelength conversion module comprises a substrate, a first matching material layer, a wavelength conversion layer, a second matching material layer and a filling rubber material channel, wherein:

the first matching material layer is positioned on the substrate;

the wavelength converting material is dispersed in the binding material;

the filling rubber material channel is connected with the first matching material layer and the second matching material layer, the filling rubber material channel and the first matching material layer are made of filling rubber materials with the same material;

the excitation light source is used for emitting an excitation light beam, wherein the excitation light beam is transmitted to the wavelength conversion module and forms an illumination light beam through the wavelength conversion module;

the light valve is positioned on the transmission path of the illumination light beam and is used for enabling the illumination light beam to form an image light beam; and

the projection lens is positioned on the transmission path of the image light beam and is used for enabling the image light beam to form a projection light beam.

13. The projection device of claim 12, wherein the first plurality of holes comprises a volume percentage of the wavelength conversion layer in a range of 5% or more.

14. The projection apparatus according to claim 12, wherein the second matching material layer comprises the filling glue material, and the first matching material layer is formed on the surface of the wavelength conversion layer after the filling glue material penetrates into a part of the plurality of first holes of the wavelength conversion layer through capillary action.

15. The projection device of claim 12, wherein the first matching material layer has a thickness greater than 0 and equal to or less than 30 microns.

16. The projection device of claim 12, wherein the refractive index of the first matching material layer is less than the refractive index of the wavelength conversion layer.

17. The projection device of claim 12, wherein the first matching material layer has a refractive index in a range of 1.1 or greater and 1.9 or less.

18. The projection device of claim 12, wherein the second matching material layer comprises silicone, epoxy, alcohol-soluble inorganic adhesive, or water-based inorganic adhesive.

19. The projection apparatus of claim 12, wherein the second matching material layer comprises silicone gel with powder of a thermally conductive material therein or epoxy resin with powder of a thermally conductive material therein.

20. The projection device of claim 12, wherein the transmittance of visible light having a wavelength band in the range of 400 nm to 700 nm through the first matching material layer or the second matching material layer is greater than 90%.